X-Linked Agammaglobulinemia (XLA)

LA is an inherited immune disorder caused by an inability to produce B cells or the immunoglobulins (antibodies) that the B cells make. The mutated gene responsible for XLA (Bruton tyrosine kinase or BTK) is located on the X chromosome. XLA is also called Bruton type agammaglobulinemia, X-linked infantile agammaglobulinemia, and congenital agammaglobulinemia.

Why Is the Study of X-Linked Agammaglobulinemia (XLA) a Priority for NIAID?

XLA is a rare genetic disease that may be chronic, debilitating, and costly. By learning more about this disease and its effects on the body, scientists gain a greater understanding of immune function that can inform multiple areas of research.

How Is NIAID Addressing This Critical Topic?

XLA is a rare genetic disease that may be chronic, debilitating, and costly. By learning more about this disease and its effects on the body, scientists gain a greater understanding of immune function that can inform multiple areas of research.

WAS is a primary immune deficiency disease (PIDD). For more information on PIDD research and patient care at NIAID, visit the NIAID PIDD site.

To learn about risk factors for XLA and current management and treatment strategies visit the National Library of Medicine, Genetics Home Reference X-linked agammaglobulinemia site.

Image of antibodies and immune cells.
Credit: NIAID
Antibodies (red) and immune cells (purple).
Causes

XLA is caused by mutations in the BTK gene found on the X chromosome. This gene normally produces a protein that is required for the development of B cells. XLA is an X-linked recessive disease. Because males only have one X chromosome, they are affected if they inherit an X chromosome containing mutated BTK.

Symptoms & Diagnosis

Infants with XLA develop frequent infections of the ears, throat, lungs, and sinuses. Serious infections also can develop in the bloodstream, central nervous system, skin, and internal organs. People with XLA have extremely low numbers of B cells, and blood tests will show extremely low levels of all types of immunoglobulins (antibodies). 

Treatment

People with XLA receive intravenous (through the vein) or subcutaneous (just under the skin) immunoglobulin regularly and antibiotics to treat infections. NIH researchers have improved methods to identify the specific microbes responsible for infections in people with XLA. By identifying hard-to-detect bacteria, physicians can prescribe the correct treatments. 

What's New: 

Content last reviewed on May 12, 2017